(1) Field of the Invention
The present invention relates to a method for transferring heat to molten metal contained in a reaction vessel, and also to an apparatus which has a reaction vessel and in which heat can be transferred to molten metal contained in the reaction vessel. More particularly, the invention relates to a method and an apparatus wherein heat can be transferred to molten metal contained in a reaction vessel in which CO gas is generated and can be combusted.
(2) Description of the Prior Arts
Recently, various proposals have been made with regard to a method for transferring heat to molten metal contained in a reaction vessel, in which CO gas generated therein can be combusted.
Some converters are equipped with a lance, for post-combustion, having nozzle holes in the lower end thereof, through which oxygen gas is blown out. CO gas generated from molten metal is post-combusted by oxygen gas blown out through the nozzle holes, and the heat produced thereby, as heat value necessary for the operation, is transferred through a layer of molten slag floating on top of the molten metal.
In the above-mentioned conventional method, amount of the CO gas generated is considerable, and the ascending speed thereof is, also, fast. As a result, the time for performing heat exchange between the high temperature post-combusted gas and foaming molten slag is undesirably shortened. Thus, this results in the efficiency in transferring heat to molten metal being low.
Japanese patent application Laid Open No. 74390/82, describes a method wherein:
(a) Fuel is supplied into a reaction vessel with molten metal already therein;
(b) A gas jet stream is blown onto the surface of the molten metal whereby the supplied fuel is gasified;
(c) The gasified gas is involved in the gas jet stream gas and a part of the gasified gas is combusted; and
(d) The gas generated by the combustion is conveyed, together with the heat produced by the gas combustion, onto the molten metal so as to transfer the heat thereto.
In the above-mentioned method, however, the gaseous atmosphere above the molten slag is heated to a high temperature by the combustion of carbon monoxide, but the molten slag lies between the molten metal and the heated gaseous atmosphere, and, in addition, contains air. This produces the disadvantage in that the transfer of heat to the molten metal is not as efficient as it could be.